Key Takeaways
- Approximately $190 billion in biologic revenue faces biosimilar competition by 2028, with oncology and immunology products accounting for 64% of that exposure.
- Biosimilar penetration in autoimmune indications reached 41% of volume in the US market in Q1 2026, up from 28% just 18 months prior.
- Originator companies deploying patient assistance programmes and formulary rebate strategies are retaining, on average, 34% more volume than those relying on brand loyalty alone.
- Regulatory acceleration at both the FDA and EMA has cut average biosimilar approval timelines by 4.2 months since 2024, compressing originators' defence windows.
The numbers circulating at this spring's biosimilar industry conferences were not projections. They were receipts. According to a 312-respondent survey conducted by a leading life sciences consultancy and published in April 2026, the pace of biosimilar market uptake has outrun almost every forecast published before 2024. In autoimmune diseases alone, volume erosion for originator products accelerated by 13 percentage points in 18 months. With at least 28 major biologics scheduled to lose primary patent protection before the end of 2028, representing a combined annual revenue base of roughly $190 billion, the industry is entering its most consequential patent cliff in history.
Oncology and Immunology Face the Steepest Revenue Erosion
Not all therapeutic categories are equally exposed. Oncology and immunology biologics together represent 64% of the total revenue at risk through 2028, according to analysis from a US-based pharmaceutical market intelligence firm tracking 47 biosimilar product launches across 11 markets. Immunology has already demonstrated how fast erosion can move: the US market for a leading anti-TNF biologic shed 38% of its branded volume within 14 months of the first biosimilar entrant achieving broad formulary placement. Oncology is expected to follow a similar trajectory, though the clinical complexity of switching protocols may slow initial uptake.
Endocrinology and haematology present a more nuanced picture. Biosimilar penetration in insulin analogues has plateaued at around 22% of volume in the US, held back by pharmacy benefit structures that continue to favour branded products through rebate arrangements. In haematology, interchangeability designations, now granted to six biosimilars in the past 12 months, are beginning to dislodge those structural barriers at a rate that has surprised payers.
Originator Defence Strategies: What the Data Actually Shows
Faced with accelerating erosion, originator companies have deployed a range of defensive tactics, with markedly uneven results. A cross-sector analysis of 19 originator product teams, published by a European healthcare economics research group in March 2026, found that companies investing in co-pay assistance programmes and hospital formulary rebate agreements retained an average of 34% more volume in year one post-biosimilar entry than those relying on brand loyalty and prescriber relationships alone. Direct-to-patient support initiatives showed the strongest correlation with retention, particularly in chronic conditions where treatment continuity is clinically significant and patients are active participants in formulary decisions.
Authorised biosimilar strategies, where the originator licenses a biosimilar version of its own product, are gaining renewed attention. Three large European originators have announced authorised biosimilar partnerships since January 2026, a tactic designed to capture a share of the lower-cost market segment without fully ceding it to independent manufacturers. The approach carries margin trade-offs, but the volume data from early adopters suggests it outperforms pure brand defence in markets where payer influence over formulary placement is strong.
"The companies that are struggling are the ones that treated biosimilar competition as a future problem. For the products we track, the erosion curve is already steeper than the most aggressive scenario we modelled in 2023. Originators that are not already 18 months into their defence execution are, in most cases, too late."
Head of Market Access Strategy at a top-ten global pharmaceutical company
Regulatory Acceleration Is Compressing the Defence Window
Regulatory timelines have shifted meaningfully in biosimilars' favour. The FDA's Centre for Drug Evaluation and Research reported in its 2025 annual performance review that average biosimilar approval times fell from 21.4 months to 17.2 months between 2023 and 2025, a reduction driven by rolling review procedures and expanded use of real-world extrapolation data for indication approvals. The EMA posted comparable improvements, trimming its median approval timeline by 3.8 months over the same period. For originators, this compression is not merely administrative: every month shaved from the approval clock is a month removed from their post-patent exclusivity runway.
The three dynamics driving the fastest erosion in 2026 share a common pattern:
- Interchangeability designation at launch: Products entering with FDA interchangeability status achieve formulary placement 40% faster than those requiring separate prescriber authorisation, based on Q1 2026 launch data across nine biosimilar products.
- Payer-led formulary exclusion of originators: At least four major US pharmacy benefit managers have moved originator biologics to non-preferred or excluded status within six months of a biosimilar achieving broad distribution, a timeline that has shortened by three months compared to the 2021 to 2023 period.
- Multi-entrant markets: Categories with three or more approved biosimilars are experiencing price erosion of 55% to 72% below originator list price, compressing the originator's rebate headroom to the point where defensive contracting becomes economically untenable.
The strategic implication for the broader biopharma sector extends well beyond the products currently on the patent cliff. Pipeline prioritisation is already shifting in response: a February 2026 survey of 88 biopharma R&D executives found that 61% have deprioritised or discontinued programmes in therapeutic areas with high near-term biosimilar exposure, redirecting capital toward novel modalities where a decade-long competitive window is more reliably available. The patent cliff, in other words, is not just reshaping the commercial landscape for today's blockbusters. It is actively redirecting the innovation bets the industry places on tomorrow's.
